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    <title>Rewrite Style Attributes</title>
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<h1>Rewrite Style Attributes</h1>



<h2>Configuration</h2>
<p>
The 'Rewrite Style Attributes' filter is enabled by specifying <em>either</em>:
<dl>
  <dt>Apache:<dd><pre class="prettyprint"
     >ModPagespeedEnableFilters rewrite_style_attributes,rewrite_css</pre>
  <dt>Nginx:<dd><pre class="prettyprint"
     >pagespeed EnableFilters rewrite_style_attributes,rewrite_css;</pre>
</dl>
or
<dl>
  <dt>Apache:<dd><pre class="prettyprint"
     >ModPagespeedEnableFilters rewrite_style_attributes_with_url,rewrite_css,rewrite_images</pre>
  <dt>Nginx:<dd><pre class="prettyprint"
     >pagespeed EnableFilters rewrite_style_attributes_with_url,rewrite_css,rewrite_images;</pre>
</dl>
<p>
in the configuration file. If both are enabled,
<code>rewrite_style_sttributes</code> takes precedence.
</p>
<h2>Description</h2>
<p>
The "Rewrite Style Attributes" filter rewrites CSS inside elements' style
attribute.  It requires <code>rewrite_css</code> to also be enabled.  See the settings for
<a href="filter-css-rewrite.html">rewrite_css</a> to control CSS minification, image rewriting,
image recompression, and cache extension.</p>
<p>
<code>rewrite_style_attributes</code> enables the filter for all style
attributes.  <code>rewrite_style_attributes_with_url</code> enables it only
for style attributes that contain the text '<code>url(</code>', for which you will generally
want to enable one or more image optimization filters.</p>
<p>
<code>rewrite_style_attributes_with_url</code> is more efficient because it
does not always parse the CSS, but it will not optimize CSS that doesn't
reference any URLs. <code>rewrite_style_attributes</code> will always parse
the CSS and optimize everything possible. Because images are generally the
source for greatest improvement and are enclosed in <code>url()</code>,
<code>rewrite_style_attributes_with_url</code> is a good balance for most uses,
while <code>rewrite_style_attributes</code> is available for more aggressive
optimization.
</p>
<h2>Operation</h2>
<p>
This filter inspects the style attributes of all tags other than
<code>&lt;style&gt;</code> (since they cannot have a style attribute) and
rewrites them according to the configured <a href="filter-css-rewrite.html"
>rewrite_css</a> filter, which can include CSS minification, image rewriting,
image recompression, and cache extension.
</p>
<p>
As explained above, if <code>rewrite_style_attributes_with_url</code> is
enabled the style attribute's contents are first scanned to ensure that they
contain the text <code>url(</code> and are processed only if so.
</p>
<p>
For example, if a <code>&lt;div&gt;</code> tag looks like this:
</p>
<pre class="prettyprint">
&lt;div style=&quot;background-image: url('images/Puzzle.jpg');&quot;/&gt;
</pre>
<p>
Then, if the image is optimizable, PageSpeed will convert it to something
like:
<pre class="prettyprint">
&lt;div style=&quot;background-image:url('images/Puzzle.jpg.pagespeed.ic.7X5cYtoCx-.jpg');&quot;/&gt;
</pre>
<h3>Example</h3>
<p>
You can see the filter in action at <code>www.modpagespeed.com</code> on this
<a href="https://www.modpagespeed.com/examples/rewrite_style_attributes.html?ModPagespeed=on&amp;ModPagespeedFilters=rewrite_style_attributes_with_url,rewrite_css,rewrite_images">example</a>.
</p>

<h2>Risks</h2>
<p>
This filter is considered minimal risk.
<code>rewrite_style_attributes_with_url</code> is a core filter but
<code>rewrite_style_attributes</code> is not.
</p>


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